class Multiwoven::Integrations::Source::AwsAthena::Client

def check_connection(connection_config)
  connection_config = connection_config.with_indifferent_access
  athena_client = create_connection(connection_config)
  athena_client.list_work_groups
  ConnectionStatus.new(status: ConnectionStatusType["succeeded"]).to_multiwoven_message
rescue StandardError => e
  ConnectionStatus.new(status: ConnectionStatusType["failed"], message: e.message).to_multiwoven_message
end

def create_connection(connection_config)
  Aws.config.update({ credentials: Aws::Credentials.new(connection_config[:access_key], connection_config[:secret_access_key]), region: connection_config[:region] })
  @database = connection_config[:schema]
  @output_location = connection_config[:output_location]
  Aws::Athena::Client.new
end

def create_streams(records)
  group_by_table(records).map do |_, r|
    Multiwoven::Integrations::Protocol::Stream.new(name: r[:tablename], action: StreamAction["fetch"], json_schema: convert_to_json_schema(r[:columns]))
  end
end

def discover(connection_config)
  connection_config = connection_config.with_indifferent_access
  query = "SELECT table_name, column_name, data_type, is_nullable FROM information_schema.columns WHERE table_schema = '#{connection_config[:schema]}' ORDER BY table_name, ordinal_position;"
  db = create_connection(connection_config)
  results = query_execution(db, query)
  catalog = Catalog.new(streams: create_streams(results))
  catalog.to_multiwoven_message
rescue StandardError => e
  handle_exception(e, {
                     context: "AWS:ATHENA:DISCOVER:EXCEPTION",
                     type: "error"
                   })
end

def group_by_table(records)
  result = {}
  records.each_with_index do |entry, index|
    table_name = entry["table_name"]
    column_data = {
      column_name: entry["column_name"],
      data_type: entry["data_type"],
      is_nullable: entry["is_nullable"] == "YES"
    }
    result[index] ||= {}
    result[index][:tablename] = table_name
    result[index][:columns] = [column_data]
  end
  result
end

def query(db, query)
  records = []
  query_execution(db, query).map do |row|
    records << RecordMessage.new(data: row, emitted_at: Time.now.to_i).to_multiwoven_message
  end
  records
end

def query_execution(db, query)
  response = db.start_query_execution(
    query_string: query,
    query_execution_context: { database: @database },
    result_configuration: { output_location: @output_location }
  )
  query_execution_id = response[:query_execution_id]
  loop do
    response = db.get_query_execution(query_execution_id: query_execution_id)
    status = response.query_execution.status.state
    break if %w[SUCCEEDED FAILED CANCELLED].include?(status)
  end
  transform_results(db.get_query_results(query_execution_id: query_execution_id))
end

def read(sync_config)
  connection_config = sync_config.source.connection_specification
  connection_config = connection_config.with_indifferent_access
  query = sync_config.model.query
  query = batched_query(query, sync_config.limit, sync_config.offset) unless sync_config.limit.nil? && sync_config.offset.nil?
  db = create_connection(connection_config)
  query(db, query)
rescue StandardError => e
  handle_exception(e, {
                     context: "AWS:ATHENA:READ:EXCEPTION",
                     type: "error",
                     sync_id: sync_config.sync_id,
                     sync_run_id: sync_config.sync_run_id
                   })
end

def transform_results(results)
  columns = results.result_set.result_set_metadata.column_info.map(&:name)
  rows = results.result_set.rows.map do |row|
    row.data.map(&:var_char_value)
  end
  rows.map { |row| columns.zip(row).to_h }
end